Question

The large quadriceps muscle in the upper leg terminates at
itslower end in a tendon attached to the upper end of the tibia
(Fig.P8.27a). The forces on the lower leg when the leg is extended
aremodeled as in Figure P8.27b, where is the force
oftension in the tendon, is the force
ofgravity acting on the lower leg, and is the force
ofgravity acting on the foot. Find when the
tendonis at an angle of 25.0° with the tibia, assuming that
=
28.0 N, F = 10.5 N, and the leg is extended at an
angle
of40.0° with the vertical. Assume that the center of gravity ofthe
lower leg is at its center, and that the tendon attaches to
thelower leg at a point one fifth of the way down the leg.
N